Snow-removal apparatus



Oct. 23, 1945. w. M. VENABLE SNOW-REMOVAL APPARATUS Filed May 16, 1944 5Sheets-Sheet 1 Oct. 23, 1945. w. M. VENABLE SNOW-REMOVAL APPARATUS sSheet-Sheet 2 Filed May 16, 1944 W A M N M N A A m m fil am m.

NN NN S QNMQ NM mm m M on 1 1945- l w. M. VENABLE 2,387,422

SNOW-REMOVAL APPARATUS Filed May 16 1944 3 Sheets$heet 3 "\iVENTOR m,W197i Patented Oct. 23, 1945 SN OW-REMOVAL APPARATUS William MayoVenable, Pittsburgh, Pa., assignor to Blaw-Knox Company, Pittsburgh,Pa., a corporation of New Jersey Application May 16, 1944, Serial No.535,826

7 Claims.

This invention relates to an improvement in snow-removal apparatus, andparticularly to the type adapted to be pushed by a truck, tractor,

or locomotive, and to throw snow to either side of the right of way,employing a rotary impeller (sometimes called a fan) rotating in avertical plane at right angles to the path of travel of the device, andmeans for feeding snow laterally across the front of the apparatus andinto the impeller inlet.

Apparatus of this general character is not I broadly new, an earlyexample being shown in Figures 8 and 9 of Patent 1,413,007, issued toHarry D. Curtis, April 18, 1922. Another early example is described inPatent 1,587,449, issued June 1, 1926, to Dan Wandsheer, to whichoriginal designs there have been numerous improvements. At the presenttime there are in practical use several designs of snow-removal machinesembodying the essential features of Curtis and Wandsheer with otherfeatures. In general, the efiiciency of such machines measured by thepercentage of power delivered to the machine which is converted intouseful work in actually discharging snow, is low, and the capacity ofthe machines relative to their size is small. The primary object of thisinvention is to increase the efficiency of such machines so that a moreefiective throw can be obtained with an engine of a given size, and agreater capacity for a machine of given size and weight.

Snow-removal machines of this general type are at present used chieflyin clearing snow from streets and highways. They either throw snowsideways off the paved road into vacant land on either side, or if thereis no adjoining vacant land, they are equipped with chutes by means ofwhich the snow is thrown into trucks, to be hauled away. The width ofhighways seldom exceeds 60 feet, and only a moderate length of throw isrequired for work of this kind. The capacity of the machine need notexceed that of the hauling facilities provided by available trucks. Forthe removal of snow from the runways of airports, however, theconditions are more severe. These runways may be two or three hundredfeet wide, and the maximum practicable length of throw is desired. Inorder to keep an airport open, moreover, the removal ,of snow must beaccom-- plished very rapidly, in case of a quick, heavy snowfall.

This invention is intended to provide a machine especially suitable forairport work, though not necessarily limited thereto, and particularly amachine so constructed that'it may be operated at a higher speed oftravel and will have greater capacity than has been practicablehitherto, with a greater length of throw and with less scatteringeffect. A further object is to reduce the difliculties encountered inhandling with one machine snow of different degrees of compactness andmoisture content. There is great variation in the character of snow atthe time of its removal, its condition then depending on many variablefactors, such as (a) the character of the snow at the time of snowfall(if the ground and the weather are cold, the snow does not packseriously even when windrowed by push plows); (b) the weather after thesnowfall until the time of removal; and (c) the amount of rehandling,thawing, and freezing that has taken place before the snow is removed.Because of these variable conditions, the density of snow to be handledmay vary from as little as 10 pounds to as much as 40 pounds per cubicfoot, and its consistency from dust to slush or loose, porous ice.

The invention may be fully understood from the following detaileddescription which refers to the accompanying drawings representing theactual construction of a working embodiment powered by a gasolineengine, which was actually built and operated in throwing snow. Whilethe proportions of a commercial machine may vary from those shown in thedrawings, the latter represent a form of the invention which provedsuccessful under test.

In the drawings,

Figure 1 is a plan view of the machine in outline;

Figure 2 is a side elevation;

Figure 3 is a longitudinal section through the machine on line HI-III ofFigure 1;

Figure 4 is a front elevation with some parts omitted; and

Figure 5 is a transverse section through the thrower impeller takenalong the plane of line V-V of Figure 4.

Referring to the drawings, a frame I0 on which the entire device issecured, comprises longitudinal members II and Ila, connecting plates I2 and Ila and cross members 13. The rear of this frame is supported uponwheels l4 journaled on an axle 15 secured to the frame. The frontportion is supported upon casters IS. The casters permit the front endof the machine to swing in any direction for steering purposes. They arejournaled in brackets 11 which are vertically adjustable by means ofjack screws [8 threaded in nuts carried in housings l9 and havinghandwheels 20. Thus the front end of the machine may be adjusted to thedesired elevation by turning th handwheels. Any other means foradjusting the height of the casters may be employed, e. g., hydrauliccylinders and pistons which can be operated rapidly and conveniently byvalves placed at a distance. The adjustment of the casters as to heightmay be made sufficient to elevate the snow-handling equipment to anydesired height above the road when the machine is being transported toworking location but is not operating to remove the snow.

In the machine shown in the drawings, the casters l6 are located behindthe snow-throwing mechanism for reasons of convenience and theavailability of space. In a large machine, the sizes of the operatingparts, especially the impeller with reference to the width of the car,are relatively smaller, and the casters may therefore be placed furtherforward than shown in the drawings. The apparatus may be pushed forwardby any convenient propulsion means, such as a motor truck. Suitablemeans such as longitudinal extension members 2| and a cross member 2Iaare provided for connection to the truck. An engine 22 mounted near therear end of the frame It) supplies power for throwing snow. Certainfeatures of the apparatus covered by the foregoing description are morefully described and claimed in my copending application, Serial No.535,827, filed May 16, 1944, for Snow-removal apparatus. A pinion 23secured to the engine shaft meshes with a. gear 23a on a shaft 24 fortransmitting power to the thrower mechanism. The ratio of these gearsmay be chosen to give the desired speed of rotation to the impeller. Theshaft 24 is journaled in bearings 25 mounted on the upper plate l2. Anysuitable bearings may be employed, but I have shown two standardantifriction ball bearings. The shaft 24 drives a shaft 26 journaled inbearings 21, through a propeller shaft 28 including telescoping shaftmembers, two universal couplings and terminal sleeves. The shaft 26 andbearings 21 are disposed in a housing 26a carried on the cross members i3.

The invention claimed herein comprises more particularly snow handlingand throwing elements now to be described and the mechanism necessaryfor operating them by power delivered by a suitable engine which may beeither that shown at 22 in the drawings or another engine locatedelsewhere and having appropriate connection for operating said elements.

As best shown in Figure 3," the shaft 26 has an impeller 29 mounted onthe forward'end thereof. Theimpeller includes a disc 30 having a conicalhub 3| adapted to receive the end of the shaft 26, a ring 32 parallel toand forwardly of the disc, and radial blades 33 extending between thedisc and ring. The forward edges of the blades extend beyond the planeof the ring 32 and are curved as at 34, as shown in Figure 5, as will bedescribed hereafter. The impeller is enclosed in a casing 35 having anoutlet 36 to be described more fully hereafter, and supported on thehousing 26a by bolts 35b. The casing has an inlet 35a receiving theforward edges'of the impeller blades, the impeller being open on theforward side within the ring 32.

Snow is thrown into the inlet 35a by an auxiliary rotor 31 whichconsists of paired rightand left-hand conveyor flights 38 mounted on along hub or tube c, in turn supported'by the shaft 40. The two membersof each pair of flights are joined together in the middle eitherdirectly or by a narrow closure member 4|, so that snow fed laterallywill be arrested in lateral motion because of junction of the flights,and acquire rotary motion by which it is thrown, not pushed, into theinlet 35a at substantially the full-width thereof. The shaft 40 isjournaled in bearings 40a in brackets 40b secured to the frame members II, and the intermediate portion of the shaft is enclosed in a tube 400.The relative speeds of the impeller 29 and rotor 31 and'the constructionof these members are coordinated in such a manner as to bring about thisresult and to overcome the difliculties that are ordinarily encounteredin machines of this general type in causing the material to enter theimpeller in sufficient quantities to develop the capacity thereof and toachieve the highest efficiency of which the impeller is capable.

As shown in Figure 3, a casing 42 extends around the rear side of therotor 3'! except atthe inlet 35a. The construction of the rotor 31 andthe casing 42 will be described hereafter under the caption Feederrotor. Intermediate the feeder rotor and the thrower rotor is a tubularneck 43. This neck will be described in detail under the caption Neckextending to impeller inlet.

As will be more fully shown hereafter, the relationship of the parts 29to 43 is essential to the attainment of the higher capacity andefficiency which are the principal objects of this invention. It isnecessary, however, for the machine to be pushed forward and, to attainthis object, it is necessary for the snow to be removed from a spacesufficiently wide to permit the passage of the machine and propersteering thereof. With machines of this general character there isusually difiiculty in keeping the snow from packing and bulldozing atthe sides of the machine where it must cut a swath. This is particularlydifilcult if the machine is to be moved forward at a high rate of speed.To overcome this difficulty, side cutters 44 arranged with their axessubstantially vertical are preferably provided, but there are conditionsin which snowplows of this type may be operated which will notnecessarily require these side cutters, and although they are shown inthese drawings and sufficient description will be included under thecaption Side cutters to show how they function, they are also disclosedand claimed in the copending application referred to, in which suchcutters will serve the same function as in this device and an additionalfunction as well.

The rotor 31 and the side cutters 44 may conveniently be driven by thesame engine which drives the impeller 29. It is not essential to theinvention that the same motor be used to drive all of these parts, butit is essential to the invention that the speeds of rotation of thevarious rotating members he correlated so that they cooperate to producethe desired results. This correlation of the speeds will be describedunder the caption Coordination of speeds of operation.

While the particular method of driving these parts so that the speedswill be coordinated may be varied, the drawings show a simple means forcoordinating these speeds by means of mechanical drives. These includebevel gears 45 by which a shaft 46 suitably journaled in bearings 41 onmembers I3 is caused to rotate in a horizontal plane at right angles tothe shaft 26. Secured to the shaft 46 is a sprocket wheel 48 whichthrough a suitable chain and sprocket drives shaft 40 of the feederrotor 31. An adjustable idler 48a is provided to take up the slack inthe chain. To drive the vertical side cutters 44, a sprocket wheel 49 ismounted near the opposite end of the shaft 40 of the rotor 31 and isconnected by a chain to a sprocket wheel 50 on a shaft journaled inbearing brackets 52, at an elevation above the casing 42. A sprocketwheel 53 drives a sprocket 54 on a horizontal shaft 55 journaled inbearings 56. The bearings 56 are carried on plates 51 secured tobrackets 40a. The vertical cutters 44 have radial blades 44a secured toshafts 58. These shafts are driven by the shaft 55 through bevel gears59, and are journaled in bearings described hereafter.

It will be observed from the brief general description just given thatby properly selecting the sizes of the sprocket wheels, the desiredrelationships of rotational speeds of different members may be secured,within reasonable limits. The drawings do not indicate the preciserelationships of the speeds to be selected, since this matter is morefully discussed hereinafter.

ings, in order to avoid undue complexity in description.

Impeller and rotor casing Cold snow consists of solid particles orfragments of ice. If the snowfall occurs during a time when theatmospheric temperature and the ground temperature are well belowfreezing, these particles remain small and are readily blown about likedust. If the snow remains in this finely divided state until it ishandled by an impeller, the snow may be so mixed with air while passingthrough the impeller as to be handled almost like a fluid. But ifsufficient time elapses between the snowfall and the handling, thesnowflakes adhere to one another forming a porous, semi-solid mass,which must be broken up before it can be successfull thrown. If suchsnow is very cold, it may easily be broken up into fragments; but if itis warm enough to contain considerable moisture, it tends when handledto pack into larger masses or snowballs which must be kept fromagglomerating into bodies too large to pass through the impeller.

The larger masses, fragments of packed snow or porous ice, do not behavein the impeller as semi-fluid, but maintain the character of solidfragments, more or less compacted during the process of passing throughthe impeller. The distance to which a solid particle can be thrownthrough quiet air depends entirely upon its size, mass and shape, andthe velocity imparted to it by the thrower. In order to throw to asuniform a distance as possible, the velocities of all particles leavingthe thrower should be as uniform as possible. The maximum peripheralvelocity of the impeller is the maximum tangential velocity with whichany particle or agglomeration of particles may be thrown. Particles oragglomerations which leave the impeller without attaining thisperipheral velocity cannot be thrown as far as those that do.

As will be seen in the drawings, the impeller 29 comprises a disc 30rigidly connected to the drive shaft 26 so as to revolve in asubstantially vertical plane, to which disc are secured several radialthrower blades 33. Eight such blades are shown although the number isoptional. These blades diverge outwardly from the axis, so that snowentering between them, moving radially outward as the rotor turns, isnot compressed by its outward motion, but because of centrifugal forcetends to compress against the inner rim of the casing which restrainsoutward motion. If there were no outlet to the casing and the latterwere cylindrical, the show would pack tightly against the casing andslide thereon, as a flywheel of ice, as the rotor turns. In order thatthere may be a discharge there must be an opening, and the snow must beaccelerated radially relative to the rotor as it moves outward towardthe discharge opening 36. To facilitate this radial acceleration, thecasing employed in this invention is of cylindrical form for only aportion of its periphery, as shown in Figure 5.

As will be noted from Figure 5, the periphery of the disc 30 is circularand the extremities of the impeller blades 33 extend to the peripherythereof. The portion of the casing 35 adjacent one side of the outlet 36diverges from the circular form at about the point indicated at 60 toincrease the clearance between the impeller blades 33 and the casing asthe outlet is approached. The purpose of this is to allow radialacceleration of the snow as the outlet is approached, and not to bringthe casing outlet on a straight line tangential to the cylindricalsection as is usual in most throwers of this general type which do notallow a gradual radial acceleration as it approaches the outlet. By thisexpedient, a larger volume of snow may be discharged than if thisgradual divergence of thn casing from the rotor were not permitted. Thisresults not only in making it possible to accelerate a larger portion ofthe snow to the full peripheral speed of the end of the blades 33, butalso to increase the capacity of the thrower impeller as less snow iscarried around past the outlet 36. Although this may appear to thecasual observer to be a very minor change from existing practice, it isfound that the resulting increase in capacity and efllciency is quitepronounced.

The snow to be thrown must enter the thrower impeller as well as leaveit. One great difllculty hitherto encountered in devices of this generalcharacter has been difficulty in causing the snow to enter the impellerat a sufl'lciently high rate to charge it to capacity. To obviate thisdifficulty it has been the practice to make the inlet very large, almostas large, in fact, as the outer casing diameter, thus leaving littlespace for radial acceleration. This expedient resulted in lowering theefilciency of the impeller and is accordingly not incorporated in myinvention. As shown in the drawings, particularly Figure 4,

the diameter of the circular opening 35a into' the casing 35 ismaterially less than the diameter of the latter. The snow is thrown, notpushed, into this opening by the feeder rotor 31 turning at a high rateof speed. Figure 4 also shows that the forward edges of the throwerblades 33 are curved in such a manner as to assist the entry of the snowinstead of to retard it or splatter it by direct impact with the facesof the blades. The

curvature of the forward edges of the blades is so correlated with thespeed of rotation of the impeller and the speed at which the snow iscast into the opening by the feeder rotor that neither the forward northe back side of the curved blades impacts the snow at the point ofentry to any appreciable extent. After the snow has entered, thetendency of the blades is to carry it further in and also to prevent anyexcess from bein pushed forward out of the impeller into the space infront thereof.

.. The blades 33 present sharp cutting edges to the incoming snow, andbesides preventing the escape forward into the space in front if thereis an excess, they also chop up any heavy lumps of snow which may reachthe inlet, so as to prevent the clogging of the impeller by snowballs oraggregations too large to be handled. This also increases the efficiencyof the impeller.

As further shown in the drawings, the casing 35 for the thrower rotor isopen at the back except for a small distance which is necessary to fullyenclose the disc 30, leaving the back of the disc free, and thuspreventing any tendency to clog between the support of the blades 33 andthe easing at the rear thereof. Furthermore, the inlet 35a whichencloses the curved portion 34 of the impeller blades is frusto-conical,resulting in a more gradual radial acceleration of the snow from theinlet to the outlet. This conical inlet may be made Venturi-shaped withadvantage.

The casing 35 as a whole is preferably so supported that it may berotated to bring the discharge outlet into different positions todischarge to either side of the roadway or directly upward if desired.Means permitting such adjustment are known and a detailed disclosure istherefore unnecessary. In the illustrated embodiment, bolts 35b may beremoved to permit this angular adjustment of the casing.

Feeder rotor and casing The feeder rotor indicated generally at 31 isdisposed ahead of the impeller 29. It is designed not merely to grindfrozen snow and convey it to the space immediately in front of the inlet35a but actually to cast, not push, it thereinto, making it possible tocharge the impeller fully with snow that has not been unduly compactedat the inlet, and with a relatively smaller opening than 1 customary inmachines of this general type. The

position of the feeder rotor is clearly shown in Figures 1 through 4. Itis driven in the direction of the arrow in Figure 4, i. e., so theforward side moves downwardly.

The casing 42 for the feeder rotor 31 is shown in section in Figure 3.In general it is approximately a half cylinder and extends from end toend of the rotor around the rear side, as shown in. plan in Figure 2.The bottom edge of this casing is provided with a cutting edge 42a ofsufficient strength to act as a shovel in the snow which it will engagein use. The casing only has sufficient clearance from the flights andblades of the feeder rotor to permit free turning, and the cutting edge42a is very nearly at the same level as the bottom edges of the flights38 so that normally the flights, not the edge, out the hard bottomsnow.-

The middle portion of this casing opens into- ;the neck 43 communicatingwith the inlet 35a whereby the snow engaged by the rotor 31 is cast intothe opening 35a by the feeder rotor 31, the neck serving to confine thesnow and direct it toward the center of the impeller. The neck 43 andcasing 42 are substantially tangential at their bottoms.

As shown in the Figure 3, the helical flights 38 are of opposite pitchand merge into the closure plates 4|, the construction being such thatwhen the rotor is turned in the direction indicated, snow engaged by theflights will be conveyed toward the middle of the rotor. Correspondingrightand left-hand conveyor screws are paired and merge at theiradjacent ends into one of the closure plates 4|.

The closure plates 4| provide sufficient clear space in the middle oftherotor 31 to permit the discharge of large fragments and obstaclesthat may be picked up in the operation of the machine which could not bedischarged readily if the space between the flights 38 were broughtdirectly together. As shown in Figure 4, the closure plates are alsocurved so that any snow that may lodge in the rotor close to the middlethereof, as far down as the tube 40c will readily slide outward of therotor which is opposite the opening. Figure 3 shows a. rotor with threesets of helical flights on each end and three radial bladestherebetween. It will be noted that snow will thus be thrown into theneck in a practically continuous stream, one set of conveyor flights andtheir associated closure plates continuing to discharge snow through theneck until the flights associated with the next closure plates begin todischarge. The snow is not thrown merely by the closure plates, butpractically all of the snow which is enclosed between thev flights andis opposite the neck opening is thrown continuously into the latter.This is a feature which is entirely new and. greatly adds to theefliciency of the device as a whole.

It will further be noted that the discharge into the neck is not limitedto a relatively small angle, the construction being such that, unlessthe machine be pushed forward so fast as to receive a great excess ofsnow, all of the snow gathered by the rotor will be cast into the neck.If there is an excess and the height of the snow in front of the machinebe not too great, the surplus will be cast forward but the neck will notbe clogged with excess discharge. The device is thus practically freefrom the danger of clogging unless it be forced into a deep bank of snowat a rate greater than that at which it is possible to remove the snowwith the power available.

Neck extending to impeller inlet The importance of the neck 43 betweenthe casing 35 and the casing 42 will be clear from the foregoing. Theneck encloses the space between the casings, the general arrangementbeing clearly shown in Figure 3. The following features should be notedparticularly.

The bottom of the neck merges into the casing 42 in a substantiallytangential direction so that the throw of material from the latterbegins to take place at the very bottom thereof and meets with noobstruction in the neck itself. In actual operation it is found that bythis arrangement snow is thrown through practically the entire area ofthe circular opening into the casing 35 at a speed approximating theperipheral speed of the rotor 31, although not with entirely uniformdistribution. As will further be seen upon examination of Figure 1, theneck is narrower where it joins the casing 42 than where it enters thecasing 35. There is thus no tendency of the snow to pack at any place inthe neck, although the neck confines the snow and insures that all of itthat is cast rearwardly by the feeder rotor enters the impeller. Atransverse section through the neck Where it adjoins the impeller casingis substantially circular; a section where it joins the feeder rotorcasing is substantially rectangular. There is, of course. sufficientclearance between the rear end of the neck and the impeller to permitthe free rotation of the latter and the angular adjustment of the casing35 but this clearance is made as small as practicable.

It may further be remarked that, although the primary function of theimpeller and rotor is to throw snow and, when the device is operating atthe desired capacity, almost all of the power is expanded in gatheringand throwing snow with, of course, the incidental losses due tofriction, the apparatus also operates as a fan and a considerable amountof air passes with the snow through the rotor and impeller. In thisregard the impeller which operates at a very much higher peripheralspeed than the feeder rotor, creates a very much stronger draft of airand there is on this account little or no tendency for snow to escapethrough the joint between the neck and the casing 35 because air isbeing induced at that point.

Although the neck is made of such shape that the snow does not tend topack therein, it sometimes happens that wet or water-logged snow has tobe handled when the temperature has fallen after a snowfall or after thewindrowing of snow that had been partially melted, the snow then beingencrusted with a thin layer of ice on the surface but being very wetbeneath although 45 the atmospheric temperature is very much belowfreezing. When such a condition exists, there is a tendency for the snowto freeze to any cold surface with which it is brought into contact,forming a layer of ice on such surfaces, and this circumstancefrequently renders it difficult for rotary snowplows to cast wet snowsuch as "snowball snow, or slush, through discharge chutes owing to thegradual clogging up of the chutes by ice forming against their innersurfaces because of the temperature, not of the snow itself, but of theatmosphere outside. This obstruction can be avoided by maintaining themetallic surfaces engaged by the snow at a temperature above thefreezing point. For this purpose and also to protect the neck itselffrom extreme cold, the neck has an air jacket 43a. An inlet 43b isprovided for introducing the exhaust of the engine 22 into this jacketwhen necessary, although the piping from the engine to the jacket isomitted from the drawings, for the sake of clarity. Whether or not thespace enclosed by the jacket is artificially heated, the mere enclosurethereof so as to prevent rapid cooling of the neck is beneficial, as isalso the addition of a layer of thermal insulation such as asbestos ormineral wood surrounding the neck. The speeds of rotation of the rotorand impeller are sufficiently high to make them against freezing ofmaterial by surface contact.

Side cutters Machines of this general character, when used in municipaland highway work, usually operate to cast snow which has previously beenwindrowed by other types of machines, although when there has been anunusually deep fall of snow or heavy 0 drifts, they also are used tomake an initial cut through the snow. It is desirable, therefore, forthese machines to be able to cut into banks of snow that may berelatively high on one side and low, or of practically no height, on theother.

Under such conditions the obstruction caused by the bank of snow,particularly if it be high .on one side only, renders it difficult topush the machine forward and steer it properly. If the bank be high, itis also desirable that the out should be a little wider than the truckwhich pushes the machine in order to'provide room for properly steeringthe truck. The difiiculty of cutting a path of proper width is aformidable one under some circumstances that are almost sure to occur onhighways at some time during the season when snow must be removed.Furthermore, the difficulty of cutting a high bank of snow merely by thepushing of the device into it by the power of a truck behind it veryseriously limits the speed at which the device may be operated. This,

scription is included here only for the purpose of explaining how theirspeed is coordinated with the speed of the other elements of theapparatus. The shafts 58 on which the side cutters are carried. arejournaled in bearings 6| and 62. The bearings are mounted on the plates51. The shafts have horizontal cutter discs b at their lower ends. Thebottom bearings 62 are not placed beneath the cutter but above the lowerend thereof. so

that the cutter proper operates close to the roadway with no supportingmechanism beneath it.

The snow is thus cut as closely to the avement as practicable. It shouldalso be noted that the direction of rotation of these cutters as shownby arrows in Figure 1, is such as to cast the snow into the space infront of the feeder rotor.

Coordination of speeds of operation It is a particular object of thisinvention to provide a machine that will not be limited to a speed oftwo or three miles per hour in effective operation and which will notredure that the snow be deep, either by previous wind rowing orotherwise, before the machine can be operated. but which can be movedforward at any speed at which it is safe to operate the truck, providedthe amount of snow in front of it is not so great as to necessitateslowing down.

It will be observed that various features of the machine are designed tosecure this ability to operate at a high speed. The elevation of thefront it unnecessary to take special steps to protect 1y clears therunway. It is found in practice with a machine of this character havinga large rotor in front, that the rotor actually cuts a path, after itbreaks the encrusted snow, a little below the bottom of the rotor 31itself, so that although the casing may be an inch or so above thepavement the machine practically cuts the snow down to the pavementlevel, providing it does not encounter some obstruction which it cannotout. It is important in such a machine also that the wheels of the truckpushing the machine forward should have good engagement with thepavement, and, therefore, that the cut made by the plow should be ofslightly greater width than the gauge of the truck wheels and leave butvery little snow beneath those wheels which would tend to cause them toslip. It is important for these reasons that not only the arrangement ofthe rotor but the arrangement of the side cutters combine to effectcleaning of a path which will give the truck pushing the device the bestopportunity to discharge its function.

Since disposal of the snow is accomplished by the impeller it should beoperated at the speed calculated to produce the desired length of throw.In practical machines this fixes the peripheral speed of the impeller.The function of the feeder rotor is to convey the snow into the impellerso as to keep the latter fully charged and also to cut up the snow if itbe encrusted or frozen so that it enters the impeller in fragments smallenough to be handled, and of such a character as to preclude packingduring the process of throwing. To meet these conditions, I have foundthat the peripheral speed of the feeder rotor ought to be of the orderof one-third that of the impeller. In practice, this means that if themachine be designed with an impeller capable of a maximum height ofvertical throw of 81 ft.. the feeder rotor alone should have a speedthat would give a maximum throw of about 9 ft. if the throw weredirected vertically. This is a very different th ng from merely pushingthe snow to the front of the impeller opening. These figures are notfixed, the ratio of these speeds depending on the size of the machine tobe built; but in every case the peripheral speed of the feeder rotormust be made sufficient to actually cast the snow at a suflicient rateof speed into the impeller opening.

The per pheral speed of the side cutters should be somewhat lower sincetheir function is to cast the snow from the sides to the space in frontof the feeder rotor. At the same time the speed of the side cutters mustbe sufllcient to dispose of all of the snow they will encounter when thetruck is moved forward at the desired speed of operation and this meansthat their speed cannot be reduced to very much less than one-half theperipheral speed of the feeder rotor.

It will be apparent from the foregoing that my invention providessnow-removal apparatus having numerous advantages over devices knownpreviously. The screw conveyors effectively gather snow from in front ofthe apparatus, moving it rapidly from both ends towards the middle whereit is discharged forcibly by the thrower rotor through the neck and intothe inlet of the impeller. The latter is capable of discharging the snowat a considerable distance and in substantial volume, thereby effectingrapid disposal of the snow collected.

The apparatus is of simple construction and is entirely self-contained.It may easily be attached to a conventional motor truck and itsoperation does not require any special skill.

*f-"Although I have disclosed herein but a preferred embodiment of theapparatus, it will be understood that the invention may take forms otherthan that shown, changes in the design and arrangement of the partsbeing comprehended within the scope of the appended claims.

Iclaim:

1. In a snow-removal apparatus, the combination with a traveling framehaving a rotary impeller mounted thereon with its axis in line with thepath traveled by the frame, and a casing for said impeller having aperipheral discharge outlet and a front inlet surrounding the axisthereof, a feeder rotor mounted on said frame with its axis at rightangles to that of the impeller, and groups of helical flights ofopposite pitch spaced apart on the rotor and effective to feed snow fromboth ends thereof toward the middle, corresponding fiights of each groupmerging at the;

middle in a closure member substantially parallel to the axis of thefeeder rotor and having a center outlet much narrower than the frontinlet of the impeller.

2. In a snow-removal apparatus, the combination with a wheeled caradapted to travel along a roadway or the like, and a centrifugal throwermounted on said car and adapted to discharge snow laterally therefrom,of a screw conveyor extending across the front of said car having spacedpaired helical flights adapted to move snow from the ends thereof towardthe middle, said paired flights being joined to form closures at themiddle of said conveyor, a casing around the rear side of the conveyorand a tubular neck extending rearwardly from said casing to saidthrower, the neck and easing being substantially tangential at theirbottoms.

3. In a snow-removal apparatus, a traveling frame having a centrifugalthrower thereon adapted to discharge to one side of the path traveled bythe frame, said thrower including an impeller rotating within a casinghaving a peripheral discharge port, said impeller comprising a disc atits rear side, a ring spaced from but coaxial with the disc and bladesextending between the disc and ring and generally radially from theiraxis, the wall of the casing adjacent said ring having a circular inletflange projecting therefrom tapering to a diameter materially. less thanthe inner diameter of said ring.

4. In a snow-removal apparatus, a traveling frame having a centrifugalthrower thereon adapted to discharge to one side of the path traveled bythe frame, said thrower including an impeller rotating within a casinghaving a peripheral discharge port, said impeller comprising a disc atits rear side, a fiat ring spaced from but coaxial with and parallel tothe disc, and blades extending between the disc and ring and generallyradially from their axis, the forward edges of the blades extendingthrough said ring and being curved.

5. In a snow-removal apparatus, the combination with a wheeled caradapted to travel along a roadway or the like, a rotary impelleradaptedto discharge snow to one side, a feeder rotor disposed across thefront of the car having conveyor screws adapted to move snow from bothends toward the middle, a casing enclosing said impeller, a casingextending around the rear side of said rotor, and a tubular neckconnecting said casings, said neck including a bottom portionsubstantially tangent to the bottom of said casing,

6. In a snow-removal apparatus th e combination with a wheeled caradapted to travel along a roadway or the like, a rotary impeller adaptedto discharge snow to one side, a feeder rotor disposed across the frontof the-car having conveyor screws adapted to move mow from both endstoward the middle, a casing enclosing said impeller having an inlet inthe forward side thereof, a casing extending around the rear side 01'said rotor. and a tubular neck extending rearwardiy from said rotorcasing to said inlet, said neck including a bottom portion substantiallytangent to the bottom of said casing.

7. The apparatus defined by claim 6 characterized by said neck being sodimensioned and disposed relative to said inlet as to permit theinduction of air along with the snow passing into the impeller.

WILLIAM MAYO VENABLE.

